ARMOR (Androgen Receptor Modulation Optimized for Response) is Tokai’s clinical development program for the evaluation of galeterone in patients with prostate cancer.
ARMOR3-SV was Tokai’s pivotal Phase 3 clinical trial of galeterone in men with metastatic CRPC whose tumor cells express the AR-V7 splice variant, which is a truncated form of the androgen receptor that has been associated with non-responsiveness to commonly-used oral therapies for CRPC. On July 26, 2016, Tokai announced its plan to discontinue ARMOR3-SV based on the recommendation of the trial’s independent Data Monitoring Committee. Assessment of plans for galeterone, the ARDA platform and Tokai’s AR-V7 assay work are underway at this time.
ARMOR3-SV was designed to evaluate whether administration of galeterone results in a statistically significant increase in radiographic progression free survival as compared to Xtandi® (enzalutamide) in treatment-naive metastatic CRPC patients whose prostate tumor cells express the AR-V7 splice variant. ARMOR3-SV was the first pivotal trial in prostate cancer to employ a precision medicine approach for patient selection.
ARMOR2, Tokai’s Phase 2 clinical trial of galeterone, demonstrated that galeterone was well-tolerated and showed clinically meaningful reductions in levels of prostate specific antigen, or PSA, a biochemical marker used to evaluate prostate cancer patients for response to therapy. Although enrollment in the ARMOR2 trial has been closed, several patients in the ARMOR2 long-term extension are continuing treatment at this time.
In particular, in a retrospective analysis of the seven patients enrolled in the trial who were identified as having a truncated androgen receptor, six of those patients (86%) showed clinically meaningful PSA reductions of at least 50%. The seventh patient discontinued therapy due to an adverse event unrelated to treatment. In addition, of the 39 metastatic CRPC patients enrolled in ARMOR2 who had not been previously been treated with chemotherapy or either Zytiga® (abiraterone acetate) or Xtandi® (enzalutamide), 77% of those patients showed PSA reductions of at least 50%.
In ARMOR2, approximately 90% of all treatment-emergent adverse events reported were grade 1 or 2 in severity and were generally manageable and reversible. There were no reported cases of seizure or mineralocorticoid excess, adverse events associated with other currently marketed drugs for CRPC. The most recent published data from ARMOR2 are available here.